Most of automatic teller machines (ATMs) of financial institutions; automatic vending machines; and digital information equipment such as mobile phones, personal digital assistances (PDAs), digital audio players, portable game machines, and car navigation systems have image display devices, and these image display devices often have touch panels as input units. Particularly, smartphones with touch panels are becoming more popular as mobile phones. Such a touch panel usually has a film sensor member including a transparent substrate and a transparent electroconductive layer formed on the substrate (Patent Literatures 1 and 2).
Examples of known types of the touch panel include an electrostatic capacitive type, an optical type, an ultrasonic type, an electromagnetic induction type, and a resistive film type. Of these, the electrostatic capacitive touch panels, which are used as input units by detecting a change in a capacitance between the tip of a finger and a transparent electroconductive layer are currently mainly used together with the resistive touch panels. Particularly, devices called tablet PCs are generally equipped with capacitive touch panels. As substrates of film sensor members for capacitive touch panel, glass substrates are widely used in prior art. Recently, however, the use of resin films is being studied in consideration of the thickness and flexibility of substrates.
Further, image display devices generally have optical films such as λ/4 plates and λ/2 plates. Such optical films and image display devices have heretofore been studied in various ways (see Patent Literatures 3 to 18).